CVE-2023-40548

Shim: interger overflow leads to heap buffer overflow in verify_sbat_section on 32-bits systems

HIGH
7.4
CVSS Score
Published: January 29, 2024 at 02:53 PM UTC
Updated: June 27, 2026 at 11:41 AM UTC
2 products affected across 2 vendorsFedoraShim

Using Red Hat Enterprise Linux 7 by Red Hat?

Get instant alerts when new vulnerabilities affect Red Hat Enterprise Linux 7 - before attackers find them.

Real-time alertsTrack your software stackFree plan available
Severity
HIGH7.4
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

A buffer overflow was found in Shim in the 32-bit system. The overflow happens due to an addition operation involving a user-controlled value parsed from the PE binary being used by Shim. This value is further used for memory allocation operations, leading to a heap-based buffer overflow. This flaw causes memory corruption and can lead to a crash or data integrity issues during the boot phase.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 15.815.8 rc1
Affected range stops below 15.8, so it looks safe — our inference, not a vendor statement

References (12)

SSVC — Action Prioritization

SSVCNo known exploitNot automatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.4HIGHredhat
Attack Vector
LOCAL
Complexity
HIGH
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-787CWE-190

Get alerted

Stop reading CVE feeds looking for your own stack

Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.

Free plan, no card